The purpose of this project is to isolate and identify the adhesive substances on the surfaces of bacteria (ligands or adhesins) which interact with adhesive materials (receptors) on the surfaces of mammalian cells. For this purpose we are employing Streptococcus pyogenes and Escherichia coli. We have already demonstrated that lipoteichoic acid on the surface of streptococci is the mediator of adherence of this organism. We are now attempting to identify the receptor in the mammalian cell membranes with which lipoteichoic acid interacts. In E. coli, the surface adhesin has been shown to be associated with surface fimbria which interacts in most cases with a mannose-like receptor on the surfaces of animal cells. We are now attempting to define the specific structure of the fimbria that are involved in binding. One approach has been to isolate fimbria from organisms grown in the presence of sublethal concentrations of streptomycin. These fimbriae have been shown to grown longer but to lose their adhesiveness. It appears therefore that streptomycin causes the production of an aberrant protein probably due to misreading of mRNA at the ribosomal level. We are now pursuing studies of the primary structure of drug-grown fimbriae to determine whether or not misreading has occurred.